A network between electronic control units (hereinafter referred to as ECUs) in a vehicle is mainly configured by a controller area network (CAN) standard. The CAN is a network characterized by a line type network configured by connecting respective ECUs on a line.
However, an in-vehicle network device connected to the same network and an in-vehicle network device connected to a different network via a gateway (relay) device are expected to coexist in the future.
For example, a technique of performing a path selection control process of a transmission destination when received data is transmitted to a certain transmission destination is disclosed in PTL 1. PTL 1 discloses “a communication path information relay means for translating received address information on the basis of an address translation table and relaying it to a transmission destination and a packet relay means for translating address information of a received packet on the basis of a network address translation table and relaying it to a transmission destination.” Specifically, an IP address of a reception side device is translated into an IP address of a transmission destination through the address translation table, and data is transferred.